PROJECT SUMMARY/ABSTRACT The primary prevention of cardiovascular (CV) events is often more intense in individuals at lower risk and vice versa (risk-treatment paradox) in part due to unawareness of each person?s CV risk, of their preferences for prevention interventions, and of their feasibility in each person?s daily life. Extant practice guidelines recommend that clinicians and patients work together to arrive at an effective and feasible prevention plan that is congruent with each person?s CV risk and informed preferences, a process called shared decision making (SDM). An effective and innovative tool that estimates CV risk and shows the impact and features of available lifestyle and pharmacological preventive interventions for use during the clinical encounter to enable SDM, the CV Prevention Choice tool, is available yet remains rarely used in practice. Our broad goal is to promote patient-centered care that effectively reduces the substantial burden of CV disease among Americans. This study, directly responsive to PA-19-166, seeks to identify implementation approaches that foster routine SDM about primary CV prevention in a diverse set of primary care practices across the U.S. This 5-year study ? proposed by a multidisciplinary team with expertise in preventive cardiology, SDM, and implementation science ? will draw on an implementation framework (Consolidated Framework for Implementation Research), an implementation theory (Normalization Process Theory), and an evaluation framework (RE-AIM) to design, conduct, and report a mixed method, hybrid implementation- effectiveness (Type III), stepped-wedge clustered randomized trial to determine: - Implementation effectiveness (Aim 1) by evaluating practice contexts and engagement of users in implementation strategies, implementation outcomes (e.g., reach, adoption) associated with these strategies, and how implementation fosters routine adoption of SDM and the CV Prevention Choice tool in primary care practices, and - SDM effectiveness (Aim 2) estimated by the extent to which individual CV prevention plans are feasible and congruent with each person?s estimated CV risk and preferences. By the project?s end, we expect to have (a) identified the most effective implementation strategies to embed SDM in routine practice and (b) estimated the effectiveness of SDM to achieve feasible and risk-concordant CV prevention in primary care.